The Weha Incremental Quartzite Radial Arm Finger Tip is a single-head diamond finger tip engineered for incremental edge profiling on quartzite, granite, marble, and quartz using radial arm machines. This is the reverse thread version (20x23xM12, color-coded red) — designed for use on the left-hand spindle of radial arm machines where standard right-hand thread finger tips would loosen during operation. Compatible with Fab King and similar single-head radial arm setups. Reverse Thread — Why It Matters On radial arm machines, the spindle rotation direction determines whether a standard or reverse thread finger tip is required. Using the wrong thread direction causes the finger tip to unscrew during operation — a safety hazard and source of tool damage. The red color coding on this finger tip identifies it as reverse thread at a glance, preventing mix-ups in a busy shop environment. Incremental Profile Design The incremental design uses stepped diamond segments that progressively shape the edge profile in controlled passes, rather than removing material all at once. This is particularly effective on quartzite and hard engineered stone where aggressive single-pass profiling risks chipping or micro-fracturing the edge. Specifications SKU: 30517RV Thread: Reverse (M12), 20x23mm Color code: Red (reverse thread) Head type: Single head Compatible machines: Fab King, radial arm machines with M12 spindle Applications: Granite, marble, quartz, quartzite, sink cutouts Weight: 0.5 lb Works Well With Weha Radial Arm Finger Tip (20x23xM12) — Standard thread version for right-hand spindles Weha Radial Arm Finger Tip Reverse Thread (20x23xM12) — Standard reverse thread finger tip Weha Radial Arm Finger Tip (1/2 Gas x 12mm) — Alternative thread adapter Weha Vacuum Brazed Zero Tolerance Wheel — Profile wheel for radial arm use Weha Rock Dog Router — Stone profiling machine Further Reading Which Weha Finger Bit Do You Need? CNC vs Radial Arm — Complete Buying Guide → — Full comparison of all Weha finger bits and finger tips by machine type, material, and application.
